Interleaves in a lay-up are used to

Interleaves in a lay-up are used to

• A. Increase surface roughness
• B. Promote resin-rich zones to improve toughness and delamination resistance
• C. Decrease stiffness
• D. Increase porosity

Answer: (B)

Interleaves insert thin resin-rich layers between plies, creating zones with higher local toughness at the interfaces. These resin-rich interlayers help cracks deflect, blunt, or bridge as they propagate, so more energy is needed to drive delamination. That targeted increase in interlaminar fracture toughness directly enhances delamination resistance, which is why this option best describes the purpose. Surface roughness, stiffness reduction, or increasing porosity are not the primary goals of interleaving.

Interleaves insert thin resin-rich layers between plies, creating zones with higher local toughness at the interfaces. These resin-rich interlayers help cracks deflect, blunt, or bridge as they propagate, so more energy is needed to drive delamination. That targeted increase in interlaminar fracture toughness directly enhances delamination resistance, which is why this option best describes the purpose. Surface roughness, stiffness reduction, or increasing porosity are not the primary goals of interleaving.